Google is continuing to back green energy projects, this time investing in the construction of a backbone that will carry energy produced by wind turbines off the East Coast back to shore.

The search giant said it is putting up 37.5 percent of the equity for the initial development stage of the project, but did not put a dollar amount on the investment. The development stage involves obtaining the necessary approvals to finance and begin building the line, said Rick Needham, green business operations director for Google.

"Although the development stage requires only a small part of the total estimated project budget, it represents a critical stage for the project," Needham wrote in a blog post.

The transmission line will run for 350 miles off the coast from New Jersey to Virginia, he said. It will carry power from offshore power hubs that will collect power from multiple offshore wind farms.

Without such a backbone, offshore wind developers would be forced to build individual transmission lines for each offshore wind project, he wrote.

When fully complete, the backbone could carry enough power to serve about 1.9 million households, he said.

Despite the potential, some proposed wind farms off the East Coast have met with opposition from groups who say the farms harm marine and bird life and mar the view.

Google said it is making the investment because it thinks it will offer a solid financial return while being good for the environment. The Mid-Atlantic region is ideal for offshore wind power creation because nearby coastal areas have large population centers that have already overstretched the existing grid, Needham said.

Trans-Elect is leading the backbone project and Good Energies and Marubeni Corporation are also investing in the initial development stage.